This question may be more of a paradox than it seems. Assuming I woke up and still had the same knowledge I did when I was human, my first instinct would be to panic after I figured out what had become of me. I believe it would take either obliviousness or too much wisdom to ""party"". The aesthetic may be good for a short time, but the negative would outweigh the good. If we are talking about the immortal type, etc, that is a nightmare. I feel that at first I would panic about surviving, which in the vampire world would mean not causing pain to self. I would probably procrastinate a lot, especially on coming up with some daily routine. I would have constant anxiety about gathering recources, staying out of the sun, or even hiding identity. I would have to live in fear of everything but nothing at the same time. I would have to be paranoid about how and where I travel.
Until quite some time is taken up--too much time, long after many genocides, some which I could have caused. At this point I am so bored of existing that death seems like a joyride. I would have probably contracted so many mental illnesses that at least one of them could have been one that changes my perspective so that time itself feels like it starts over, to make the decades more bearable. Or maybe it makes boredom into euphoria. If not, I would spend a great time trying to invent a way to kill myself. With growing technology, there would probably be a way to stimulate things I couldn't experience like death maybe, as well as things I would like to cut down on like consuming bodily fluids or energies. I could emulate happiness or being human again with some VR goggles and sensors, accustomed to my delicate vampire skin of course. But it would only last so long. So much time would keep going by that I would have become beyond the realms of self hatred and into the realms of pure numbness. I would have no empathy left. Probably by then would be when I would realize that the first thing I should have done when I woke up was enjoyed myself, I should have partied while I didn't know any better.
But what do I know. Being a bat might be pretty cool, however.